Source code in embedded C for unsigned integer to string

Question

Without resorting to standard library utoa, I\'m looking for source code of utoa so I may customise it for specific project. I have unsigned integer (32 bits) with output su

Answer 1

That's not terribly hard. Keep dividing by 10 and use the remainder mod 10 as an index into "0123455679". You build this up from right to left, so you have to buffer the result and return it in reverse:

char * utoa(unsigned int n)
{
  char * res, buf[30]; // long enough for largest number
  unsigned int i, counter = 0;

  if (n == 0)
    buf[counter++] = '0';

  for ( ; n; n /= 10)
    buf[counter++] = "0123456789"[n%10];

  res = malloc(counter);

  for (i = 0; i < counter; ++i)
    res[i] = buf[counter - i - 1];

  return res;
}